Many Inter-exchange Carriers (IXCs) provide their large customers with direct access through high-speed trunks, typically T1 or T3 trunks. Some IXCs, such as AT&T monitor the status of such direct access high-speed trunks within their own networks to detect and isolate troubles in an effort to avoid service outages. For example, within AT&T's network, certain types of equipment, such as the DDM 1000 multiplexer, available from Lucent Technologies, have the capability of detecting parity errors in the transmit direction on a T3 trunk and in response, generating a signal indicative of such errors in a C-bit data stream carried over the reverse path (the receive channel) of the monitored T3 trunk. By monitoring the transmitted traffic, AT&T can readily detect potential difficulties, and take appropriate action, thereby greatly reducing the incidence of path failures.
Presently, the ability of an IXC carrier to monitor the transmitted traffic beyond its own network, and particularly, to monitor such traffic at a customer premises, depends on the presence at the customer premises of equipment capable of returning a C-bit signal on a reverse path. In practice, not all customers that enjoy direct access through a high-speed trunk possess equipment capable of generating a C-bit monitoring signal, making monitoring of traffic at the customer premises impossible.
Thus, there is a need for a technique for extending the monitoring capability of an IXC to facilitate monitoring of traffic at a customer premises.